are std.traits.FieldNameTuple and std.traits.Fields returned value always in sync?

[mw via Digitalmars-d-learn]

Are their returned value, i.e the field names and their types are 
always in the same order, and of the same length?

If they are not, how to get sync-ed pairs (name, type)?
If they are, why we need two separate calls, which cause 
confusion.